Many electronic and optoelectronic devices are composed of compound semiconductor heterostructures or ferroelectric/multiferroic structures epitaxially grown on single-crystalline growth substrates. Compound semiconductors represent a large class of materials with composition ranges that can, in principle, be varied to provide a broad range of lattice parameters. Provided an appropriate growth substrate is available, such materials can be grown epitaxially using standard film growth techniques. Unfortunately, the number of available single-crystalline growth substrates for such materials is very limited, which has hindered the development of devices based on compound semiconductors having tailored lattice parameters.